BackgroundInflammatory mediators, including acute phase reactants and cytokines, have been reported to be associated with clinical efficacy in patients with melanoma and other cancers receiving immune checkpoint inhibitors (ICI). Analyses of patient sera from three large phase II/III randomized ICI trials, one of which included a chemotherapy arm, were performed to assess whether baseline levels of C-reactive protein (CRP), interleukin-6 (IL-6) or neutrophil/lymphocyte (N/L) ratios were prognostic or predictive.Patients and methodsBaseline and on-treatment sera were analyzed by multiplex protein assays from immunotherapy-naïve patients with metastatic melanoma randomized 1:1 on the Checkmate-064 phase II trial of sequential administration of nivolumab followed by ipilimumab or the reverse sequence. Baseline sera, and peripheral blood mononuclear cells using automated cell counting, were analyzed from treatment-naïve patients who were BRAF wild-type and randomly allocated 1:1 to receive nivolumab or dacarbazine on the phase III Checkmate-066 trial, and from treatment-naïve patients allocated 1:1:1 to receive nivolumab, ipilimumab or both ipilimumab and nivolumab on the phase III Checkmate-067 trial.ResultsHigher baseline levels of IL-6 and the N/L ratio, and to a lesser degree, CRP were associated with shorter survival in patients receiving ICI or chemotherapy. Increased on-treatment levels of IL-6 in patients on the Checkmate-064 study were also associated with shorter survival. IL-6 levels from patients on Checkmate-064, Checkmate-066 and Checkmate-067 were highly correlated with levels of CRP and the N/L ratio.ConclusionIL-6, CRP and the N/L ratio are prognostic factors with higher levels associated with shorter overall survival in patients with metastatic melanoma receiving ICI or chemotherapy in large randomized trials. In a multi-variable analysis of the randomized phase III Checkmate-067 study, IL-6 was a significant prognostic factor for survival.

BackgroundTherapies targeting anti-tumor T-cell responses have proven successful in the treatment of a variety of malignancies. However, as most patients still fail to respond, approaches to augment immunotherapeutic efficacy are needed. Here, we investigated the ability of histone deacetylase 6 (HDAC6)-selective inhibitors to decrease immunosuppression and enhance immune function of melanoma patient T-cells in ex vivo cultures.MethodsT-cells were harvested from peripheral blood or tumor biopsies of metastatic melanoma patients and cultured in the presence of pan-, class-specific or class-selective histone deacetylase (HDAC) inhibitors. Changes in cytokine production were evaluated by Luminex and intracellular flow cytometry staining. Expression of surface markers, transcription factors, protein phosphorylation, and cell viability were assessed by flow cytometry. Changes in chromatin structure were determined by ATAC-seq.ResultsT-cell viability was impaired with low doses of pan-HDAC inhibitors but not with specific or selective HDAC inhibitors. The HDAC6-selective inhibitors ACY-1215 (ricolinostat) and ACY-241 (citarinostat) decreased Th2 cytokine production (i.e. IL-4, IL-5, IL-6, IL-10 and IL-13). Expansion of peripheral blood T-cells from melanoma patients in the presence of these inhibitors resulted in downregulation of the Th2 transcription factor GATA3, upregulation of the Th1 transcription factor T-BET, accumulation of central memory phenotype T-cells (CD45RA-CD45RO + CD62L + CCR7+), reduced exhaustion-associated phenotypes (i.e. TIM3 + LAG3 + PD1+ and EOMES+PD1+), and enhanced killing in mixed lymphocyte reactions. The frequency, FOXP3 expression, and suppressive function of T regulatory cells (Tregs) were decreased after exposure to ACY-1215 or ACY-241. Higher frequencies of T-cells expressing CD107a + IFNγ+ and central memory markers were observed in melanoma tumor-infiltrating lymphocytes (TIL), which persisted after drug removal and further expansion. After ACY-1215 treatment, increased chromatin accessibility was observed in regions associated with T-cell effector function and memory phenotypes, while condensed chromatin was found in regions encoding the mTOR downstream molecules AKT, SGK1 and S6K. Decreased phosphorylation of these proteins was observed in ACY-1215 and ACY-241-treated T-cells. AKT- and SGK1-specific inhibition recapitulated the increase in central memory frequency and decrease in IL-4 production, respectively, similar to the observed effects of HDAC6-selective inhibition.ConclusionsHDAC6-selective inhibitors augmented melanoma patient T-cell immune properties, providing a rationale for translational investigation assessing their potential clinical efficacy.Electronic supplementary materialThe online version of this article (10.1186/s40425-019-0517-0) contains supplementary material, which is available to authorized users.

100 Background: Acute phase reactants including C-reactive protein (CRP), and chronic inflammatory proteins including IL-6, which induces production of CRP from the liver, have been associated with a poor outcome in a variety of cancers. Methods: Sera from the CheckMate 064, 066 and 067 studies were assessed at baseline and on treatment for levels of IL-6 and CRP by Luminex. Associations between IL-6 and/or CRP levels and response or survival were determined. Purified endotoxin- and azide-free CRP was also tested for its immune effects in vitro using human T cells. Results: In patients receiving sequential nivolumab then ipilimumab in CheckMate 064 (cohort A), baseline serum IL-6 was associated with response (p = 0.03); serum IL-6 at week 12 after nivolumab alone (cohort A) or ipilimumab alone (cohort B), was also associated with response (p = 0.004 and 0.006, respectively). Baseline IL-6 above the median was associated with shorter survival in cohort A (p = 0.003) and cohort B (p = 0.0001). Serum CRP above the median was associated with shorter survival in cohort A (p = 0.001). Baseline IL-6 and CRP in cohort A were associated with one another, rho = 0.71 and p < 0.0001 In the randomized CheckMate 067 study, higher baseline serum CRP above the median was associated with shorter survival for ipilimumab, nivolumab or the combination with p < 0.0001, p < 0.11, and p = 0.0034, respectively. In the randomized CheckMate 066 study, higher baseline serum CRP was associated with shorter survival for nivolumab or dacarbazine (p = 0.131 and P < 0.0001 respectively). CRP suppressed T cell immunity and function, and levels above 10 micrograms/mL suppressed T cell proliferation (p = 0.005) and altered T cell signaling as well as calcium flux (p = 0.01), suggesting that CRP affected the earliest steps in T cell signaling and activation. Conclusions: High levels of CRP and IL-6 at baseline were associated with a poor response and shorter survival after nivolumab alone, and CRP with ipilimumab alone or the combination of both drugs. High levels of CRP were also associated with shorter overall survival in the randomized CheckMate 066 study of chemotherapy compared to nivolumab. CRP and IL-6 are prognostic factors for checkpoint inhibition.

PD-1 blockade induces durable responses in patients with metastatic melanoma and prolongs relapse-free survival in patients with resected melanoma; however, current biomarkers do not consistently associate with patient responses. In this study, we investigated the impact of nivolumab therapy on peripheral blood regulatory T cells (Treg) and its relation to patient outcomes. Peripheral blood Tregs and conventional CD4 T cells from patients with resected high-risk melanoma treated with adjuvant nivolumab were assessed for gene expression changes by RNA-seq. Percentages of circulating Tregs and phosphorylated-STAT3 (pSTAT3) expression levels were assessed by flow cytometry and validated in an independent cohort of active disease patients. Suppressive function of Tregs was assessed in allogeneic mixed lymphocyte reactions. Tregs from non-relapse patients had increased expression of proliferation associated genes. An increase in the proportion of circulating Tregs and pSTAT3 expression and a reduction in Treg-suppressive capacity were observed in non-relapsing, but not relapsing patient samples 13 weeks after starting treatment. blockade of PD-1 increased Treg percentages and pSTAT3 expression, and reduced Treg-suppressive function. PD-1 blockade also led to IL10 production by T cells, resulting in higher Treg proliferation. The addition of a STAT3 inhibitor ameliorated the increase in Tregs, enhanced suppressive function, and decreased T-cell IL10 production These results demonstrate that induction of pSTAT3, reduced suppressive function, and a paradoxical increase in Treg proliferation are novel correlates of patient benefit from PD-1 blockade.

BackgroundHigh C reactive protein (CRP) levels have been reported to be associated with a poor clinical outcome in a number of malignancies and with programmed cell death protein 1 immune checkpoint blockade in patients with advanced cancer. Little is known about the direct effects of CRP on adaptive immunity in cancer. Therefore, we investigated how CRP impacted the function of T cells and dendritic cells (DCs) from patients with melanoma.MethodsThe effects of CRP on proliferation, function, gene expression and phenotype of patient T cells and DCs, and expansion of MART-1 antigen-specific T cells were analyzed by multicolor flow cytometry and RNA-seq. Additionally, serum CRP levels at baseline from patients with metastatic melanoma treated on the Checkmate-064 clinical trial were assessed by a Luminex assay.ResultsIn vitro, CRP inhibited proliferation, activation-associated phenotypes and the effector function of activated CD4+ and CD8+ T cells from patients with melanoma. CRP-treated T cells expressed high levels of interleukin-1β, which is known to enhance CRP production from the liver. CRP also suppressed formation of the immune synapse and inhibited early events in T-cell receptor engagement. In addition, CRP downregulated the expression of costimulatory molecules on mature DCs and suppressed expansion of MART-1-specific CD8+ T cells in a dose-dependent manner by impacting on both T cells and antigen-presenting cells. High-serum CRP levels at baseline were significantly associated with a shorter survival in both nivolumab-treated and ipilimumab-treated patients.ConclusionsThese findings suggest that high levels of CRP induce an immunosuppressivemilieuin melanoma and support the blockade of CRP as a therapeutic strategy to enhance immune checkpoint therapies in cancer.Trial registration numberNCT01783938andNCT02983006.